The EGGS differ much in size, colour, and numbers. They are holoblastic, with unequal cleavage, but those species which possess an unusual amount of food-yolk, for instance _Rhacophorus schlegeli_ and the Apoda, approach the meroblastic type of segmentation. As a rule, the greater the amount of yolk, the smaller is the number of eggs produced. But the number which is laid {54}during one season is not only difficult to calculate, but it varies individually, old females laying more than young specimens. Moreover, some kinds, _e.g._ the Discoglossidae, spawn several times in one year. _Alytes_, _Rhinoderma_, _Hylodes_, _Rhacophorus_, _Pipa_, in fact those kinds which are remarkable for special nursing habits, lay only a few dozen eggs at a time. _Hyla arborea_ produces up to 1000, _Rana temporaria_ about 3000, _Bufo vulgaris_ averages 5000, _Bufo viridis_ and _Rana esculenta_ up to 10,000 and more. T. H. Morgan[26] has observed a _Bufo lentiginosus_ which laid 28,000 eggs within ten hours! The number of eggs produced by the Apoda and Urodela is comparatively moderate, in the average a few dozen, _Amblystoma_ alone laying about 1000. The eggs possess a gelatinous mantle of variable thickness and consistency. In _Amphiuma_ they are strung together like the beads of a rosary, and the envelope hardens into a kind of shell. Many Newts and some Anura fasten their eggs singly on to plants and other objects in the water, with or without threads of stiffening mucus. In many Anura, _e.g._ Bufonidae, they pass out as closely-set strings of beads, one string out of each oviduct; in others, _e.g._ Ranidae, they are disconnected, and form large, lumpy masses, especially when the gelatinous mantle swells up in the water. The use of this mantle seems to be chiefly the protection of the growing embryo, which in many species, when hatched out of the egg proper, drops into and remains for some time in the softened jelly. Possibly the latter affords some nutriment to the early larva. Concerning the mode of FECUNDATION it is to be remarked that copulation proper takes place only in the Apoda. For the Urodela Boulenger[27] has given the following summary. In no case does actual copulation take place. The male deposits the spermatophores which it is the office of the female to secure:– I. No amplexus, but a lengthy courtship in the water; the male is more brilliantly coloured than the female, and ornamented with dorsal and caudal crests, or other appendages: _Triton_, cf. also systematic part. II. Amplexus takes place; there are no marked sexual differences in colour and no ornamental dermal appendages. A. Amplexus of short duration, partly on land, but deposition of the sperma in the water. No accessory sexual characters: Terrestrial Salamanders, namely _Salamandra_, _Chioglossa_, _Salamandrina_. _Spelerpes_ breeds in damp caves without water. {55}B. Amplexus of lengthy duration and in the water.